Purging fluid circuits in wellbore control devices

ABSTRACT

The disclosure relates to purging a RCD including a bearing of contaminants with a fluid circuit, the fluid circuit having at least one housing adjacent to the RCD, a first plurality of valves within the bearing, a second plurality of valves within the housing, at least one inlet port located on the RCD, each inlet port being connected to the housing, at least one outlet port located on the RCD, each outlet port being connected to the housing, and a purge outlet in fluid communication with the fluid circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. provisional application no. 61/792,940 filed Mar. 15, 2013 the disclosure of which is hereby incorporated by reference.

STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not Applicable.

REFERENCE TO A “SEQUENCE LISTING”, A TABLE, OR A COMPUTER PROGRAM

Not Applicable.

BACKGROUND

Technical Field

The subject matter generally relates to systems and techniques in the field of oil and gas operations. When a well site is completed, pressure control equipment may be placed near the surface of the earth. The pressure control equipment may control the pressure in the wellbore while drilling, completing and producing the wellbore. The pressure control equipment may include blowout preventers (BOP), rotating control devices (RCDs), and the like. The RCD is a drill-through device with a rotating seal that contacts and seals against the drill string (drill pipe with tool joints, casing, drill collars, Kelly, etc.) for the purposes of controlling the pressure or fluid flow to the surface.

RCDs and other pressure control equipment are used in underbalanced drilling (UBD) and managed pressure drilling (MPD), which are relatively new and improved drilling techniques, and work particularly well in certain offshore drilling environments. Both technologies are enabled by drilling with a closed and pressurizable circulating fluid system as compared to a drilling system that is open-to-atmosphere at the surface. Managed pressure drilling is an adaptive drilling process used to more precisely control the annular pressure profile throughout the wellbore. MPD addresses the drill-ability of a prospect, typically by being able to adjust the equivalent mud weight with the intent of staying within a “drilling window” to a deeper depth and reducing drilling non-productive time in the process. The drilling window changes with depth and is typically described as the equivalent mud weight required to drill between the formation pressure and the pressure at which an underground blowout or loss of circulation would occur. The equivalent weight of the mud and cuttings in the annulus is controlled with fewer interruptions to drilling progress while being kept above the formation pressure at all times. An influx of formation fluids is not invited to flow to the surface while drilling. Underbalanced drilling (UBD) is drilling with the hydrostatic head of the drilling fluid intentionally designed to be lower than the pressure of the formations being drilled, typically to improve the well's productivity upon completion by avoiding invasive mud and cuttings damage while drilling. An influx of formation fluids is therefore invited to flow to the surface while drilling. The hydrostatic head of the fluid may naturally be less than the formation pressure, or it can be induced.

Due to the nature of oilfield drilling, sealing elements within the RCD often become worn and need to be replaced. When doing so, the bearing is removed from the RCD body, and a new bearing is reinstalled into the RCD body. After reinstallation, one existing problem is that the hydraulic fluid circuit needs to be cleansed of contaminants in the nature of wellbore fluid and debris before lubrication and drilling operations recommence. There exists a need for an improved contaminant removal system and method to remove contaminants from the RCD

US Pub. No. 2006/0144622 proposes a system and method for cooling a RCD while regulating the pressure on its upper radial seal. Gas, such as air, and liquid, such as oil, are alternatively proposed for use in a heat exchanger in the RCD. A hydraulic control system is proposed to provide fluid to energize a bladder of an active seal to seal around a drilling string and to lubricate the bearings in the RCD.

U.S. Pat. Nos. 6,554,016 and 6,749,172 propose a rotary blowout preventer with a first and a second fluid lubricating, cooling, and filtering circuit separated by a seal. Adjustable orifices are proposed connected to the outlet of the first and second fluid circuits to control pressures within the circuits.

The above discussed U.S. Pat. Nos. 6,554,016 and 6,749,172, and Pub. No. US 2006/0144622 are incorporated herein by reference for all purposes in their entirety. All of the above referenced patents and patent publications have been assigned to the assignee of the current invention.

BRIEF SUMMARY

The disclosure relates to purging a RCD including a bearing of contaminants with a fluid circuit, the fluid circuit having at least one housing adjacent to the RCD, a first plurality of valves within the bearing, a second plurality of valves within the housing, at least one inlet port located on the RCD, each inlet port being connected to the housing, at least one outlet port located on the RCD, each outlet port being connected to the housing, and a purge outlet in fluid communication with the fluid circuit.

As used herein, the terms “line” and “circuit” may be interpreted to mean any structural form used in the transport of fluid including flexible conduits such as hosing or tubing, drilled channels, ports, orifices, voids, outlets, vents and the like.

As used herein the term “RCD” or “RCDs” and the phrases “pressure control equipment”, “pressure control apparatus” or “pressure control device(s)” shall refer to well related pressure control equipment/apparatus/device(s) including, but not limited to, rotating-control-device(s), active rotating control devices, blowout preventers (BOPs), and the like.

BRIEF DESCRIPTION OF THE FIGURES

The embodiments may be better understood, and numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings. These drawings are used to illustrate only typical embodiments of this invention, and are not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

FIG. 1 depicts a schematic overview of an embodiment of a RCD hydraulic purge system.

FIG. 2 depicts a schematic overview of an embodiment of a fluid circuit which may be used in the purge system.

FIG. 3 depicts a schematic overview of an embodiment of a lubrication fluid circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The description that follows includes exemplary apparatus, methods, techniques, and instruction sequences that embody techniques of the inventive subject matter. However, it is understood that the described embodiments may be practiced without these specific details.

FIG. 1 depicts a schematic overview of an embodiment of a RCD hydraulic purge system or fluid circuit 100. The purge system 100 is connected to a pump 102. The pump 102 in FIG. 1 pumps a volume of purge fluid 105 through purge system 100 to facilitate the cooling and lubrication of RCD bearing 124. Examples of a RCD body or RCD 122 with a bearing 124 may be U.S. Pat. Nos. 6,554,016 B1 and 6,749,172 B1, and Pub. No. US 2006/0144622 A1. The purge fluid 105 may be the same fluid used for lubrication or any other suitable contaminant removal fluid as known to those having ordinary skill in the art. For simplicity and advantageous operation, as seen in FIG. 3, the supply line 104, bleed line 106 and return line 108 used in the purge system 100 in one embodiment may be the exact same lines as used in the working RCD lubricating (and/or cooling) circuit. Referring back to FIG. 1, the pump 102 is connected to the supply line 104 and a tank 103 of purge or lubrication fluid 105. The purge system 100 empties or may be emptied via a purge line 110 or the like into a waste area 132. Waste area 132 may be any area or container suitable for housing the purge fluid 105 with contaminants for further processing, or it may be the wellbore itself. The hydraulic lines 101 may include a supply line 104, a bleed line 106, a return line 108, and a purge line or purge outlet 110 and may have hose diameters selected by one skilled in the art to best achieve the desired flow pressure and rate for pressure controlled drilling conditions, lubrication, seal activation, and purging operations.

The flow of the fluid through purge system 100 may be controlled by a four-port directional control valve 112 connected to supply line 104 and bleed line 106. The bleed line 106 is connected to filter 114 and the return line 108 is connected to filter 116. The size and type of filters 114 and 116 may be adjusted as desired so as to prolong the usable lifetime of said filters. The hydraulic lines of purge system 100 are connected to valves 118 a-h housed within manifold valve blocks or housing(s) 120 a-b. While the embodiment in FIG. 1 illustrates the valves 118 a-h as housed within manifold valve blocks 120 a-b, it is to be appreciated that the components may also be discrete elements, components or housed in cartridges. In FIG. 1, valves 118 are shown as pilot-to-open check valves, but it is to be appreciated that any kind of valves which can be manipulated to allow and/or prevent or otherwise control, the flow of fluid may be used including check valves, pilot-to-close check valves, relief valves, manual, remote, or automatic valves. Valve blocks 120 a and 120 b flank RCD body 122 which contains inlet/outlet ports 126 that allow for fluid to travel through the supply journal region 130 c, bleed journal region 130 a and return journal region 130 b between the RCD body 122 and bearing(s) 124 (i.e. outside but around the bearing(s)). Although the embodiment in FIG. 1 illustrates the valve blocks 120 on opposite sides of RCD body 122 with inlet ports 126 a separated by generally one-hundred-and-eighty degrees from the outlet ports 126 b, both facing the respective valve blocks 120, the valve blocks 120 and inlet/outlet ports 126 may be positioned in any manner such that fluid may travel between the valve blocks 120 and inlet/outlet ports 126. Further, the valve blocks 120 may be bolted or otherwise secured to the side of the RCD body 122. The hydraulic lines 101, including supply line 104, bleed line 106 and return line 108, connect to the bearing 124 and to the bearing lubrication circuit valves 128 housed within RCD body 122. The bearing 124, along with the bearing lubrication circuit valves 128, may be inserted into and removed out of RCD body 122 as required by the demands of the drilling operation. The bearing lubrication circuit valves 128 may also be any kind of valves which may be manipulated to allow and/or prevent or otherwise control the flow of fluid. Further, the purge system 100 may have one or more pressure gauges 134 installed on the supply line 104, bleed line 106, return line 108, or purge line 110 to monitor the pressure at a particular point in the lines 104, 106, 108 or 110. Moreover, the purge system 100 may include one or more pressure-temperature gauges or PT gauge 136 on the supply line 104, bleed line 106, return line 108 or purge line 110 to monitor the pressure and/or temperature at a particular point in the lines 104, 106, 108 or 110.

FIG. 2 depicts a schematic overview of an embodiment of the purge fluid 105 flow path 200 through the purge system 100. When the purge system 100 initiates, the pump 102 begins circulation of purge fluid 105 through the supply line 104 until it reaches the four-port directional control valve 112. The control valve 112 redirects the purge fluid 105 flowing in from supply line 104 into the bleed line 106. The purge fluid 105 then travels through the bleed line 106 and through valve 118 a in valve block 120 a. Thus, the purge fluid 105 travels through valve block 120 a and through the inlet/outlet ports 126 on RCD body 122, to the outer periphery of bearing 124. When purging, the bearing lubrication circuit valves 128 are closed to the flow of fluid through the bearing 124, so as to allow the purge fluid 105 to circulate through the bleed journal region 130 a captured between RCD body 122 and bearing 124. Circulation of the purge fluid 105 through the journal regions 130 removes wellbore fluids and debris, such as drill cuttings, from the journal regions 130 captured between bearing 124 and RCD body 122 and prepares the RCD body 122 for a subsequent lubrication cycle. After the purge fluid 105 circulates through the bleed journal region 130 a, the pump 102 continues to move the purge fluid 105 out of the RCD body 122 via inlet/outlet ports 126 and to valve block 120 b. In valve block 120 b, the valve 118 b is piloted to open to allow the purge fluid 105 to next flow through valve 118 c back to the RCD body 122 and around bearing 124. As the bearing lubrication circuit valves 128 are kept in a closed position 129 to the passage of fluid in FIG. 2, the purge fluid 105 will circulate around return journal region 130 b. The purge fluid 105 then flows out of the RCD body 122 into valve block 120 a, where the purge fluid 105 then flows through valve 118 d. After passing through valve 118 d, the purge fluid 105 flows into RCD body 122 and circulates through supply journal region 130 c. The purge fluid 105 then exits the RCD body 122 to valve block 120 b. In the embodiment shown, the purge fluid 105 then flows through valve 118 e (which is piloted to open), and through valve 118 f. The purge fluid 105 exits the purge system 100 via one of the hydraulic lines 101, for example, the purge line 110, emptying and/or dumping contaminants and/or cuttings from the drilling equipment to waste area 132.

The purge system 100 as described utilizes or integrates the existing lubrication circuit and pump in the RCD body 122, without the need for expensive or time consuming modifications to the existing hydraulic lubrication circuitry. Such existing RCD lubricating circuits contemplated include U.S. Pat. Nos. 6,554,016 and 6,749,172,and Pub. No. US 2006/0144622. FIG. 3 also illustrates one such lubricating circuit 400 with lubrication flow path 402, wherein the bearing circuit lubrication valves 128 are in an open position 127, allowing purge or lubrication fluid 105 to circulate within the bearing 124, thus cooling and lubricating the bearing 124 and RCD body 122.

Further, in one embodiment at least one sensor, flow meter or detection device 300, for example, an electrical, mechanical, or hydraulic sensor, may be positioned in the purge line 110. It is contemplated that the sensor or sensors could be mechanical, electrical, or hydraulic and may be used additionally for measuring temperature, pressure, density, flow rate, particulate matter, and/or fluid levels. In one working example, an operator may wish to quantify the flow of the purge fluid 105 via a flow metering or detection device 300 (e.g. to determine when five gallons of purge fluid 105 have flowed through the meter).

In a working example, the bearing(s) 124 may run in the working environment for a period of from about two days to about three weeks prior to removal and insertion of the same and/or other bearing(s) 124. Preferably but not limited to absolutely, the purge system 100 will be performed when the bearing assembly(ies) 124 are inserted before lubrication begins (by way of example only, purged once using five gallons of purge fluid 105).

While the embodiments are described with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventive subject matter is not limited to them. Many variations, modifications, additions and improvements are possible. For example, while the embodiments described are in reference to RCDs with lubrication circuits, it will be understood that the inventive system, method, and apparatus are equally applicable to cooling circuits in RCDs, to dual lubricating and cooling circuits in RCDs, to other equipment with fluid circuitry such as seal activation circuits in BOPs (see e.g. U.S. Pat. Nos. 6,554,016 and 6,749,172, which are incorporated herein by reference) and latch mechanism control circuits (see e.g. U.S. Pub. Nos. 2006/0144622 and 2012/0013133, which are incorporated herein by reference), amongst others, including non-rotating control devices which contain hydraulic feeds. Further by way of example, the techniques used herein may be applied to equipment needing lubrication and/or purging, as used in mining, food, or construction industries.

Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter. 

What is claimed is:
 1. An apparatus for purging a RCD containing a bearing with a fluid circuit, the fluid circuit comprising: at least one housing adjacent to the RCD; a first plurality of valves within the bearing; a second plurality of valves within the housing; at least one inlet port located on the RCD, each inlet port being connected to the housing; at least one outlet port located on the RCD, each outlet port being connected to the housing; and a purge outlet in fluid communication with the fluid circuit.
 2. The apparatus as claimed in claim 1, further comprising a hydraulic line in fluid communication with the fluid circuit, wherein the hydraulic line is routed through the second plurality of valves within the housing.
 3. The apparatus as claimed in claim 2, wherein the first plurality of valves within the bearing is in a closed position during purging of the RCD.
 4. The apparatus as claimed in claim 3, further comprising: one or more journal regions located between the bearing and the RCD, wherein the journal regions are in fluid communication with the hydraulic line and further wherein the journal regions are configured to capture debris.
 5. The apparatus as claimed in claim 4, wherein the one or more inlet ports are in fluid communication with the fluid circuit, each inlet port connecting the housing and the journal regions; and further wherein the one or more outlet ports are in fluid communication with the fluid circuit, each outlet port connecting to the housing and the journal regions.
 6. The apparatus as claimed in claim 5, wherein the hydraulic line further comprises: a supply line connected to the fluid circuit; a bleed line connected to the fluid circuit; and a return line connected to the fluid circuit.
 7. The apparatus as claimed in claim 6, further comprising a directional control valve, wherein the directional control valve is configured to allow redirection of fluid flow from the supply line to the bleed line.
 8. The apparatus as claimed in claim 1, wherein the fluid circuit is a lubricating fluid circuit of the RCD, and further wherein the first plurality of valves within the bearing is configured to be in an open position during lubrication of the bearing.
 9. The apparatus as claimed in claim 1, wherein the at least one housing is attached to the RCD.
 10. The apparatus as claimed in claim 1, wherein the second plurality of valves is pilot-operated check valves.
 11. A system for purging contaminants from a lubricating circuit of a RCD using a purge fluid, comprising: at least one valve block adjacent to the RCD; a plurality of valves housed within the valve block, said plurality of valves configured for controlling a fluid flow; and at least one hydraulic line routed through the plurality of valves and the RCD.
 12. The system as claimed in claim 11, further comprising a pump connected to the hydraulic line, wherein the pump is configured for pumping the purge fluid.
 13. The system as claimed in claim 12 wherein the at least one hydraulic line comprises a supply line attached to the pump configured for supplying the purge fluid to the RCD.
 14. The system as claimed in claim 13, wherein the at least one hydraulic line further comprises a hydraulic line configured for removing contaminants and the purge fluid from the RCD.
 15. The system as claimed in claim 14, further comprising: a bearing within the RCD; and one or more journal regions between the bearing and the RCD.
 16. The system as claimed in claim 15, wherein the plurality of valves is further configured to control the fluid flow around the journal regions to remove contaminants.
 17. The system as claimed in claim 16, wherein the supply line is configured to supply the purge fluid through the plurality of valves in the valve block to the journal regions.
 18. The system as claimed in claim 17, wherein the purge fluid is a lubricating and cooling fluid.
 19. A method of purging a RCD containing a bearing with a fluid circuit containing a first plurality of valves, comprising the steps of: pumping a purge fluid through a housing containing a second plurality of valves; circulating the purge fluid from the housing around the bearing with the fluid circuit; and emptying the purge fluid from the RCD after the purge fluid exits the RCD.
 20. The method as claimed in claim 19, further comprising the steps of controlling the purge fluid with the first and second plurality of valves.
 21. The method as claimed in claim 20, wherein the step of circulating the purge fluid through the housing also comprises removing contaminants, and further wherein the step of emptying the purge fluid from the RCD after the purge fluid exits the RCD also comprises emptying the contaminants from the RCD after the purge fluid and the contaminants exit the RCD.
 22. The method as claimed in claim 21, further comprising the step of preventing the flow of fluid through the first plurality of valves in the fluid circuit.
 23. The method as claimed in claim 19, wherein the fluid circuit is a pre-existing cooling and lubricating fluid circuit for the RCD; wherein said step of pumping the purge fluid through the housing is performed utilizing the pre-existing cooling and lubricating fluid circuit; and wherein said step of circulating the purge fluid from the housing is performed utilizing the pre-existing cooling and lubricating fluid circuit.
 24. The method as claimed in claim 23, wherein the pre-existing cooling and lubricating fluid circuit has at least a hydraulic supply line, a hydraulic bleed line and a hydraulic return line, and further wherein the step of pumping the purge fluid through the housing further comprises the steps of: pumping the purge fluid into the supply line; and redirecting the purge fluid from the supply line into the bleed line.
 25. The method as claimed in claim 23, further comprising the step of preparing the RCD for a subsequent lubrication cycle.
 26. The method as claimed in claim 19, wherein the step of circulating the purge fluid from the housing around the bearing comprises circulating the purge fluid through a journal region between the bearing and the RCD.
 27. The method as claimed in claim 19, wherein the step of circulating the purge fluid from the housing around the bearing with the fluid circuit also comprises the step of cooling the bearing as the purge fluid circulates around the bearing.
 28. A method of purging contaminants from a RCD comprising the steps of: utilizing a preexisting fluid circuit having at least a hydraulic supply line and a hydraulic return line; pumping a purge fluid with an existing pump into the supply line; redirecting the purge fluid to another line; moving the purge fluid in a unitary direction through at least one RCD towards a purge outlet; and dumping the contaminants via the purge outlet. 